Bug 1280129 - Update tasks to use v2 treeherder routes r=dustin
Jobs reporting to treeherder should rely on the task route for project,
revision, and pushlog ID rather than things stuffed into task.extra.treeherder.
This also removes the need for a revision_hash that was calculated by mozilla-taskcluster.
MozReview-Commit-ID: EcQM9QRZzgG